I just bought a 2nd hand 24" 2007 alu iMac 2.4ghz. Didn't know, and wasn't told the HDD was dying, their were scratches on the front screen & it was missing the bolts holding the rear of the chassis to the front aluminium casing. But apart from all that nightmare my big problem is the screen flickers like crazy when it boots and for up to 10 minutes after. It appears to settle down and then runs ok but it seems the time it takes to settle is getting longer and I'm terrified its a dying dog. To me it looks like a power issue of some sort, the graphics card is definitely displaying a picture behind the flickering, the OS is loading perfectly, sound is present etc. Think of the flickering like a damaged neon light flicker but faster. Does anyone have any idea if I could fix this relatively easily/cheaply or indeed what exactly is going on. The other option is to try get a refund or sue the guy who sold it to me as being in good condition.